Efficient Synthesis of Pinoresinol, an Important Lignin Dimeric Model Compound

Pinoresinol is a high-value monolignol-derived lignan used in plant defense and with human health-supporting effects. The synthetic yield and isolation efficiency of racemic pinoresinol from coniferyl alcohol by conventional radical coupling methods is sub-optimal. In this work, a facile and efficient synthetic approach was developed to synthesize pinoresinol with much higher yield. By using 5-bromoconiferyl alcohol, which was synthesized in high yield from 5-bromovanillin, to make 5,5′-bromopinoresinol via a peroxidase-mediated radical coupling reaction takes advantage of the smaller variety of radical coupling products from the 5-substituted monolignol, producing simpler product mixtures from which 5,5′-bromopinoresinol may be readily crystalized with good yield (total yield of 44.1% by NMR; isolated crystalline yield of 24.6%). Hydro-debromination of the crystalline 5,5′-bromopinoresinol to pinoresinol was essentially quantitative. Gram quantities of pinoresinol were conveniently synthesized by using this approach. This simple alternative pathway to make pinoresinol will impact pinoresinol-related research including structural characterization and modification of lignins, as well as clinical applications of pinoresinol and its derivatives.

Triplet photosensitization mechanism of thymine by an oxidized nucleobase: from a dimeric model to DNA environment

An efficient triplet–triplet energy transfer between 5-formyluracil and a stacked thymine nucleobase is revealed by this theoretical study.

A simple dimeric model accounts for the vibronic ECD spectra of chiral polythiophenes in their aggregated states

Aggregates of chiral polythiophenes (PTs) show exciton-coupled electronic circular dichroism (ECD) spectra with a unique vibronic structure, which can be reproduced by quantum dynamical simulations on the coupled states of small dimeric models.

Copper(ii) coordination properties of the Aβ(1–16)2 peptidomimetic: experimental evidence of intermolecular macrochelate complex species in the Aβ dimer

The coordination features of the copper(ii) complexes with a Aβ(1–16)2 dimeric model are reported for the first time.